WO2021149718A1

WO2021149718A1 - Shock absorber

Info

Publication number: WO2021149718A1
Application number: PCT/JP2021/001831
Authority: WO
Inventors: ミルトンムジィヴィジィワ; 浩一山香; 片山　洋平
Original assignee: 日立Astemo株式会社
Priority date: 2020-01-24
Filing date: 2021-01-20
Publication date: 2021-07-29
Also published as: KR20220088499A; JPWO2021149718A1; US20230037408A1; KR102668004B1; DE112021000715T5; CN114981560A; JP7223883B2

Abstract

According to the present invention, a piston bolt is divided into a first member and a second member, a first small-diameter part and a large-diameter part of a shared passage are formed in the first member, and a second small-diameter part of the shared passage is formed in the second member, wherefore the shared passage can be machined by a general-purpose construction method and tool, and the labor required for the piston bolt can be reduced.

Description

Buffer

The present invention relates to a shock absorber that controls the flow of oil and liquid with respect to the stroke of the piston rod to adjust the damping force.

Patent Document 1 discloses a shock absorber in which a common passage is formed in a shaft portion of a piston bolt. The flow of oil and liquid in the common passage is controlled by a valve spool (valve body) movably provided in the common passage.

JP-A-2019-173786

The above-mentioned common passage is composed of a plurality of axial passages having different inner diameters. Since each axial passage is machined by inserting a tool in one direction from the front side (head of the piston bolt), it is special for machining the axial passage (large diameter part) on the back side. Construction methods and tools are required, and it is difficult to ensure accuracy. In addition, the increase in man-hours has increased the manufacturing cost, which has been a factor in lowering the productivity.

An object of the present invention is to provide a shock absorber capable of reducing the man-hours of a piston bolt.

The shock absorber according to the embodiment of the present invention includes a cylinder in which a working fluid is sealed, a piston that is slidably fitted in the cylinder and divides the inside of the cylinder into two chambers, and one end of the piston. In the piston rod which is connected and the other end extends outward from the cylinder, the extension side passage and the contraction side passage provided in the piston, the piston bolt inserted into the shaft hole of the piston, and the extension side passage. The extension side main valve provided, the extension side back pressure chamber for adjusting the valve opening pressure of the extension side main valve, the contraction side main valve provided in the contraction side passage, and the valve opening pressure of the contraction side main valve. The contraction side back pressure chamber to be adjusted, the common passage connecting the extension side back pressure chamber and the contraction side back pressure chamber, the valve shaft movably provided in the common passage, and the valve shaft are opened. A damping force adjusting shock absorber comprising a valve spring urging in a direction, a piston valve for controlling the flow of oil and liquid in the common passage, and an actuator for controlling the movement of the valve shaft. At one end of the valve body of the shaft in the axial direction, a first valve portion that restricts the flow of working fluid to and from the first valve seat formed on the piston bolt when the actuator is not energized is provided, and the valve is provided. On the other end side in the axial direction of the body, a second valve portion that restricts the flow of working fluid to and from the second valve seat formed on the piston bolt when the actuator is energized is provided, and the piston bolt is provided. , The first member is composed of a first member and a second member, the first member is formed with the first valve seat, and the second member is formed with the second valve seat. ..

According to one embodiment of the present invention, the man-hours for the piston bolt can be reduced.

It is sectional drawing of the main part in the shock absorber of 1st Embodiment. It is an enlarged view of the damping force adjusting mechanism in FIG. It is explanatory drawing of 1st Embodiment, and is the cross-sectional view by the shaft plane of a piston bolt. It is explanatory drawing of 2nd Embodiment, and is the cross-sectional view by the shaft plane of a piston bolt. It is explanatory drawing of 3rd Embodiment, and is the cross-sectional view by the shaft plane of a piston bolt.

(First Embodiment) This will be described with reference to the figure to which the first embodiment of the present invention is attached.
For convenience, the vertical direction in FIG. 1 is referred to as "vertical direction". Although the first embodiment is a single-cylinder type damping force adjusting type shock absorber, it can also be applied to a double-cylinder type damping force adjusting type shock absorber provided with a reservoir.

As shown in FIG. 1, a piston 3 is slidably fitted in the cylinder 2. The piston 3 divides the inside of the cylinder 2 into two chambers, a cylinder upper chamber 2A and a cylinder lower chamber 2B. A free piston (not shown) that can move in the cylinder 2 in the vertical direction is provided in the cylinder 2, and the free piston has a cylinder lower chamber 2B on the piston 3 side and a gas chamber on the bottom side in the cylinder 2. It is divided into (not shown).

The shaft portion 6 of the piston bolt 5 is inserted into the shaft hole 4 of the piston 3. The piston bolt 5 has a head portion 7 provided at the upper end portion of the shaft portion 6, an upper first cylindrical portion 8 formed on the outer peripheral edge portion of the head portion 7, and a lower second cylindrical portion 9. .. The lower end of the solenoid case 94 is connected to the first cylindrical portion 8 by screw coupling. The shaft portion 6 of the piston bolt 5 is provided with a common passage 11 that is arranged coaxially with the shaft portion 6 and extends in the axial direction (vertical direction).

As shown in FIG. 2, the common passage 11 has a first small diameter portion 12 formed in the upper part of the common passage 11 and opened at the upper end, and a second small diameter portion 12 formed in the lower part of the common passage 11 and closed at the lower end. Each axial passage consists of a portion 14, a large diameter portion 13 communicating the first small diameter portion 12 and the second small diameter portion 14. The inner diameter of the common passage 11 is the largest in the large diameter portion 13, and decreases in the order of the first small diameter portion 12 and the second small diameter portion 14. The common passage 11 (first small diameter portion 12) opens at the bottom surface of the recess 10 formed in the head 7 of the piston bolt 5. The recess 10 is formed in a circular shape whose cross section in a plane perpendicular to the axis is coaxial with the piston bolt 5.

As shown in FIG. 1, the lower end (one end) of the piston rod 15 is connected to the upper end of the solenoid case 94 by screw coupling. The upper end side (the other end) of the piston rod 15 extends from the cylinder 2 to the outside. A locking nut 16 is attached to the lower end of the piston rod 15. A small diameter portion 17 is formed at the lower end of the piston rod 15. A sealing member 18 for sealing between the solenoid case 94 and the piston rod 15 is mounted on the annular groove (reference numeral omitted) formed on the outer peripheral surface of the small diameter portion 17.

The piston 3 is provided with an extension side passage 19 whose upper end opens toward the cylinder upper chamber 2A side and a contraction side passage 20 whose lower end opens toward the cylinder lower chamber 2B side. On the lower end side of the piston 3, an extension side valve mechanism 21 for controlling the flow of oil liquid (working fluid) in the extension side passage 19 is provided. On the other hand, on the upper end side of the piston 3, a contraction side valve mechanism 51 for controlling the flow of oil liquid in the contraction side passage 20 is provided.

As shown in FIG. 2, the extension side valve mechanism 21 includes an annular seat portion 24 formed on the outer peripheral side of the lower end surface of the piston 3 and an extension side main valve 23 that abuts on the seat portion 24 so as to be detachably seated. The extension-side pilot body 25 attached to the shaft portion 6 of the piston bolt 5 and the extension-side back pressure chamber 26 formed between the extension-side pilot body 25 and the back surface of the extension-side main valve 23 are provided. The pressure in the extension-side back pressure chamber 26 acts on the extension-side main valve 23 in the valve closing direction.

A nut 27 is attached to the lower end of the shaft portion 6 of the piston bolt 5. A washer 28, a retainer 29, and a disc valve 30 are provided between the nut 27 and the extension side pilot body 25 in this order from the lower side. The washer 28, the retainer 29, and the disc valve 30 are held between the nut 27 and the inner peripheral edge of the extension side pilot body 25. The extension-side main valve 23 is a packing valve in which an annular packing 31 made of an elastic body comes into contact with the inner peripheral surface of the extension-side pilot body 25 over the entire circumference.

The extension side back pressure chamber 26 communicates with the cylinder lower chamber 2B via a passage 32 and a disc valve 30 formed in the extension side pilot body 25. The disc valve 30 opens when the pressure in the extension side back pressure chamber 26 reaches a predetermined pressure, and relieves the pressure in the extension side back pressure chamber 26 to the cylinder lower chamber 2B. The extension-side back pressure chamber 26 communicates with a radial passage 34 formed in the shaft portion 6 of the piston bolt 5 via a disk-shaped extension-side back pressure introduction valve 33. The radial passage 34 communicates with the second small diameter portion 14.

The extension side back pressure introduction valve 33 is a check valve that allows the flow of oil liquid from the cylinder lower chamber 2B to the extension side back pressure chamber 26 via the passage 44 of the extension side pilot body 25. The extension side back pressure introduction valve 33 is an annular seat portion formed on the inner peripheral side of the passage 32 and the outer peripheral side of the passage 44 on the upper surface of the extension side pilot body 25 (the surface on the extension side back pressure chamber 26 side). Seated at 35. The inner peripheral edge of the extension-side back pressure introduction valve 33 is held between the inner peripheral edge of the extension-side pilot body 25 and the spacer 36. The extension-side back pressure chamber 26 includes a plurality of extension-side introduction orifices 37 formed on the inner peripheral side of the extension-side back pressure introduction valve 33, and an annular passage 38 formed on the inner peripheral edge of the extension-side pilot body 25. It communicates with the radial passage 34 via.

The second small diameter portion 14 communicates with a radial passage 39 (contraction side discharge passage) formed in the shaft portion 6 of the piston bolt 5. The radial passage 39 is provided in the annular passage 41 formed at the lower end of the shaft hole 4 of the piston 3, the plurality of notches 42 formed on the lower end side of the inner peripheral edge of the piston 3, and the piston 3. It is communicated with the extension side passage 19 via the contraction side check valve 40. The contraction-side check valve 40 comes into contact with the seat portion 24 and the annular seat portion 43 provided on the inner peripheral side of the extension-side aisle 19 on the lower end side of the piston 3 so as to be able to take off and sit. The contraction side check valve 40 allows the flow of oil liquid from the radial passage 39 to the extension side passage 19.

The contraction side valve mechanism 51 includes an annular seat portion 54 formed on the outer peripheral side of the upper end surface of the piston 3, a contraction side main valve 53 that abuts on the seat portion 54 so as to be detachably seated, and a shaft portion 6 of the piston bolt 5. A contraction-side pilot body 55 attached to the valve and a contraction-side back pressure chamber 56 formed between the contraction-side pilot body 55 and the back surface of the contraction-side main valve 53 are provided. The pressure in the contraction side back pressure chamber 56 acts on the contraction side main valve 53 in the valve closing direction.

A washer 45 is fitted on the inner peripheral side of the second cylindrical portion 9 of the piston bolt 5. The shaft portion 6 of the piston bolt 5 is inserted into the shaft hole 46 of the washer 45. The washer 45 and the second cylindrical portion 9 are sealed by an annular sealing member 47 provided on the outer circumference of the washer 45. A disc 58, a retainer 59, and a disc valve 60 are provided between the washer 45 and the contraction side pilot body 55 in this order from the upper side. The disc 58, retainer 59, and disc valve 60 are held between the washer 45 and the inner peripheral edge of the contraction side pilot body 55. The contraction side main valve 53 is a packing valve in which an annular packing 61 made of an elastic body comes into contact with the inner peripheral surface of the contraction side pilot body 55 over the entire circumference.

The contraction side back pressure chamber 56 communicates with the cylinder upper chamber 2A via a passage 62 and a disc valve 60 formed in the contraction side pilot body 55. The disc valve 60 opens when the pressure in the contraction side back pressure chamber 56 reaches a predetermined pressure, and relieves the pressure in the contraction side back pressure chamber 56 to the cylinder upper chamber 2A. The contraction-side back pressure chamber 56 communicates with a radial passage 64 formed in the shaft portion 6 of the piston bolt 5 via a disk-shaped contraction-side back pressure introduction valve 63. The radial passage 64 communicates with the first small diameter portion 12.

The contraction side back pressure introduction valve 63 is a check valve that allows the flow of oil liquid from the cylinder upper chamber 2A to the contraction side back pressure chamber 56 via the passage 74 of the contraction side pilot body 55. The contraction side back pressure introduction valve 63 is an annular seat portion formed on the inner peripheral side of the passage 62 and the outer peripheral side of the passage 74 on the lower surface of the contraction side pilot body 55 (the surface on the contraction side back pressure chamber 56 side). Seated at 65. The inner peripheral edge portion of the contraction side back pressure introduction valve 63 is held between the inner peripheral edge portion of the contraction side pilot body 55 and the spacer 66. The contraction-side back pressure chamber 56 includes a plurality of contraction-side introduction orifices 67 formed on the inner peripheral side of the contraction-side back pressure introduction valve 63, an annular passage 68 formed on the inner peripheral edge of the contraction-side pilot body 55, and an annular passage 68. It communicates with the radial passage 64 via the width across flats 75 formed on the shaft portion 6 of the piston bolt 5.

The first small diameter portion 12 communicates with a radial passage 69 (contraction side discharge passage) formed in the shaft portion 6 of the piston bolt 5. The radial passage 69 is provided in the annular passage 71 formed at the upper end of the shaft hole 4 of the piston 3, the plurality of notches 72 formed on the upper end side of the inner peripheral edge of the piston 3, and the piston 3. It is communicated with the contraction side passage 20 via the extension side check valve 70. The extension-side check valve 70 comes into contact with the seat portion 54 on the upper end side of the piston 3 and the annular seat portion 73 provided on the inner peripheral side of the contraction-side passage 20 so as to be able to take off and sit. The extension side check valve 70 allows the flow of oil liquid from the radial passage 69 to the contraction side passage 20.

The flow of oil and liquid in the common passage 11 of the piston bolt 5 is controlled by the pilot valve 81 (pilot valve). The pilot valve 81 has a valve spool 82 (valve shaft) slidably fitted in the common passage 11. The valve spool 82 is composed of a solid shaft, and together with the piston bolt 5, constitutes the pilot valve 81. The valve spool 82 can be detached and seated on the sliding portion 83 of the first small diameter portion 12 inserted above the radial passage 64 and the second valve seat 118 formed on the opening peripheral edge of the second small diameter portion 14. It has a valve body 85 that comes into contact with the valve body 85, and a connecting portion 86 that connects the sliding portion 83 and the valve body 85.

A valve spring 88 made of a compression coil spring is interposed between the spring receiving portion 87 formed on the valve body 85 of the valve spool 82 and the bottom portion of the common passage 11 (second small diameter portion 14). The valve spring 88 urges the valve spool 82 in the valve opening direction (“upward” in FIG. 2). As a result, the end surface 89 of the sliding portion 83 comes into contact with (presses) the lower end surface 93 of the operating rod 92 of the solenoid 91 (actuator). In the present embodiment, a configuration is shown in which a thrust is generated by energizing the coil 95 to operate the operating rod 92. However, as a means for operating the operating rod 92, for example, the spring constant of the valve spring is used as an actuator. It may be switched by, or it may be performed by a mechanism that controls the oil pressure.

As shown in FIG. 1, the solenoid 91 has a solenoid case 94, an operating rod 92, and a coil 95. A plunger 96 is coupled to the outer peripheral surface of the operating rod 92. The plunger 96 generates thrust by energizing the coil 95. An inner rod passage 97 is formed on the inner peripheral side of the operating rod 92. The actuating rod 92 is guided in the vertical direction (axial direction) by the bush 100 provided in the core 98.

A spool back pressure chamber 101 is formed on the inner peripheral side of the core 99 of the solenoid 91. The spool back pressure chamber 101 includes a plurality of notches 102 provided at the lower end of the operating rod 92, a passage in the rod 97, a rod back pressure chamber 103 formed in the core 98, and a passage extending in the core 98 in the radial direction. The cylinder upper chamber 2A is communicated with the cylinder upper chamber 2A via an upper chamber side communication passage including the 104 and the air bleeding orifice 105 formed on the side wall of the solenoid case 94.

As shown in FIG. 2, a spool back pressure relief valve 107 (check valve) and a spacer 108 are provided between the head portion 7 of the piston bolt 5 and the washer 45 in this order from the upper side. The inner peripheral edge of the spool back pressure relief valve 107 is held by the spacer 108 and the inner peripheral edge of the head 7 of the piston bolt 5. On the other hand, the outer peripheral edge portion of the spool back pressure relief valve 107 comes into contact with the annular seat portion 109 formed on the lower surface of the head portion 7 of the piston bolt 5 so as to be detachably seated. An annular passage 110 is formed between the head portion 7 of the piston bolt 5 and the washer 45 to serve as a space for opening the spool back pressure relief valve 107. The spool back pressure relief valve 107 is a check valve that allows the flow of oil and liquid from the spool back pressure chamber 101 to the annular passage 110.

The spool back pressure chamber 101 includes a recess 10 of the piston bolt 5, a plurality of passages 111 formed in the head 7 of the piston bolt 5, a spool back pressure relief valve 107, an annular passage 110, and an inner peripheral edge of the upper end surface of the washer 45. A plurality of notches 112 formed in the portion, a plurality of passages 113 formed in the washer 45, a plurality of notches 114 formed in the inner peripheral edge of the lower end surface of the washer 45, and a shaft portion of the piston bolt 5. The width across flats 75 formed in No. 6, the annular passage 68 formed in the contraction side pilot body 55, the radial passage 64, the first small diameter portion 12, the radial passage 69, the annular passage 71 formed in the piston 3, and the annular passage 71. The piston lower chamber 2B is communicated with the lower chamber side communication passage including the notch 72, the extension side check valve 70, and the contraction side passage 20.

A fail-safe valve 121 is provided on the head 7 of the piston bolt 5. The fail-safe valve 121 includes a disc-shaped fail-safe spring 122 and a spring fixing member 123 fixed to the upper end of the valve spool 82. The spring fixing member 123 is coupled to the valve spool 82 by caulking the inner peripheral edge portion on the upper end side over the entire circumference or partially. The outer peripheral edge of the fail-safe spring 122 is supported by a step portion 127 (opening edge portion of the recess 10) formed in the head portion 7 of the piston bolt 5. Further, the outer peripheral edge portion of the fail-safe spring 122 is held between the core 99 and the step portion 127 via the spacer 128.

Then, when the coil 95 is not energized, the spring receiving portion 125 of the spring fixing member 123 is seated on the seat portion 126 formed in the core 99 by the spring force of the fail-safe spring 122. As a result, the fail-safe valve 121 is closed, and the communication between the upper chamber side communication passage and the lower chamber side communication passage is cut off. Further, the first valve portion 115 of the valve body 85 of the valve spool 82 is seated on the first valve seat 116 of the piston bolt 5. As a result, the communication between the extension side back pressure chamber 26 and the contraction side back pressure chamber 56 is cut off.

On the other hand, when the coil 95 is energized, the second valve portion 117 of the valve body 85 of the valve spool 82 is seated on the second valve seat 118 of the piston bolt 5 by the thrust of the operating rod 92 (plunger 96). As a result, the communication between the extension side back pressure chamber 26 and the contraction side back pressure chamber 56 is cut off. Here, the valve opening pressure of the pilot valve 81 (valve body 85) is controlled by changing the current value of energizing the coil 95. In the soft mode in which the current value of energizing the coil 95 is small, the spring force of the valve spring 88 and the thrust of the operating rod 92 are in equilibrium, and the valve body 85 is separated from the second valve seat 118 (see FIG. 2). ).

Next, the pilot flow of the oil liquid in the first embodiment will be described. (Shrinking stroke) Before opening the pilot valve 81, the oil liquid in the lower chamber 2B of the cylinder is charged with the shrinking side passage 20, the orifice 76 of the extension side check valve 70, the notch 72 of the piston 3, the annular passage 71, and the diameter. Directional passage 69, first small diameter portion 12 (common passage 11), and contraction side introduction passage, that is, radial passage 64, width across flats 75 of shaft portion 6, annular passage 68, and contraction side back pressure introduction valve 63. It is introduced into the contraction side back pressure chamber 56 through the contraction side introduction orifice 67. Further, the oil liquid introduced into the first small diameter portion 12 includes the contraction side introduction orifice 67 of the contraction side back pressure introduction valve 63, the annular passage 68, the width across flats 75 of the shaft portion 6, and the notch 114 of the washer 45. And, it flows to the cylinder upper chamber 2A through the disk 58.

When the pilot valve 81 is opened, the oil liquid introduced into the first small diameter portion 12 is introduced into the contraction side back pressure chamber 56 via the contraction side introduction passage, and the contraction side pilot passage, that is, the large diameter portion 13 (Common passage 11), second small diameter portion 14 (common passage 11), radial passage 39, annular passage 41, notch 42 of piston 3, contraction side check valve 40, and extension side passage 19 on the cylinder. It flows to room 2A. Here, the valve opening pressure of the pilot valve 81 can be adjusted by controlling the current value of energizing the coil 95 of the solenoid 91. At the same time, the pressure of the oil liquid introduced from the contraction side back pressure introduction valve 63 into the contraction side back pressure chamber 56 is also adjusted, so that the valve opening pressure of the contraction side main valve 53 can be controlled.

(Extension stroke) Before opening the pilot valve 81, the oil liquid in the cylinder upper chamber 2A is supplied with the extension side passage 19, the orifice 48 of the contraction side check valve 40, the notch 42 of the piston 3, the annular passage 41, and the diameter. Extend through the directional passage 39, the second small diameter portion 14 (common passage 11), and the extension side introduction passage, that is, the radial passage 34, the annular passage 38, and the extension side introduction orifice 37 of the extension side back pressure introduction valve 33. It is introduced into the lateral back pressure chamber 26. Further, the oil liquid in the cylinder upper chamber 2A flows to the cylinder lower chamber 2B via the upper chamber side communication passage and the lower chamber side communication passage described above.

When the pilot valve 81 is opened, the oil liquid introduced into the second small diameter portion 14 is introduced into the extension side back pressure chamber 26 via the extension side introduction passage, and the extension side pilot passage, that is, the large diameter portion 13 (Common passage 11), first small diameter portion 12 (common passage 11), radial passage 69, annular passage 71, notch 72 of piston 3, extension side check valve 70, and contraction side passage 20 under the cylinder. It flows to room 2B. Here, the valve opening pressure of the pilot valve 81 can be adjusted by controlling the current value of energizing the coil 95 of the solenoid 91. At the same time, the pressure of the oil liquid introduced from the extension side back pressure introduction valve 33 into the extension side back pressure chamber 26 is also adjusted, so that the valve opening pressure of the extension side main valve 23 can be controlled.

Next, the piston bolt 5 constituting the first embodiment will be described with reference to FIG.
The piston bolt 5 is composed of a first member 131 and a second member 132. The first member 131 and the second member 132 are configured to be separable in the axial direction (“vertical direction” in FIG. 3) at an intermediate position of the shaft portion 6. On the other hand (head 7 side), the first member 131 is provided with a first small diameter portion 12 and a large diameter portion 13 of the common passage 11. On the other hand (the tip end side of the shaft portion 6), the second member 132 is provided with the second small diameter portion 14 of the common passage 11.

A large diameter portion 13 of the common passage 11 opens at the lower end surface 133 of the first member 131. In other words, an annular lower end surface 133 forming a right angle to the axis (center line) of the piston bolt 5 is formed at the lower end (the other end in the axial direction) of the large diameter portion 13. The first valve seat 116 is formed on the first member 131. The first valve seat 116 is provided at the lower end (the other end in the axial direction) of the first small diameter portion 12. Then, the first valve portion 115 provided at the upper end (one end in the axial direction) of the valve body 85 (see FIG. 1) is seated on the first valve seat 116 provided on the piston bolt 5, whereby the first small diameter portion 12 The flow of the oil liquid between the and the second small diameter portion 14 is blocked (restricted).

On the other hand, a cylindrical convex portion 132 coaxial with the piston bolt 5 is formed on the inner peripheral side of the upper end surface 134 (one end surface in the axial direction) of the second member 132. In other words, the second member 132 is formed with an annular upper end surface 134 that is perpendicular to the axis (center line) of the piston bolt 5. The upper end (one end in the axial direction) of the second small diameter portion 14 opens at the end surface 136 of the convex portion 135. The second valve seat 118 is provided at the upper end (one end in the axial direction) of the second small diameter portion 14. Then, the second valve portion 117 provided on the tapered portion (the other end side in the axial direction) of the valve body 85 (see FIG. 1) is seated on the second valve seat 118 provided on the piston bolt 5, whereby the first valve body 85 (see FIG. 1) is first. The flow of the oil liquid between the small diameter portion 12 and the second small diameter portion 14 is blocked (restricted).

Then, in order to connect the first member 131 and the second member 132 to form the piston bolt 5, the convex portion 135 of the second member 132 is press-fitted (inserted) into the large diameter portion 13 of the first member 131. The annular lower end surface 133 (the other end surface in the axial direction) of the first member 131 and the annular upper end surface 134 (one end surface in the axial direction) of the second member 132 are brought into contact with each other (butting each other). As a result, the common passage 11, that is, the coaxiality of the first small diameter portion 12, the large diameter portion 13, and the second small diameter portion 14, and the first small diameter portion 12 as the spool sliding surface on the first member 131 side, The squareness of the convex portion 135 as the valve seat surface (second valve seat 118) on the second member 132 side with the end surface 136 is secured. The butt portion 137 between the first member 131 and the second member 132 is joined by brazing using a brazing material such as copper. In addition to brazing, welding or adhesion may be used as the joining method.

Here, in the conventional piston bolt composed of one member, a tool (tool) is inserted in one direction from the head side in order to process a common passage, so a special construction method and tool for processing a large diameter part. Was necessary, and it was difficult to ensure accuracy. In addition, since the man-hours for the piston bolts increase, the productivity decreases, which causes an increase in the manufacturing cost of the shock absorber. Further, since the large diameter portion is formed at the intermediate position in the axial direction of the common passage, it is difficult to approach the large diameter portion, and man-hours are required for inspection.

On the other hand, in the first embodiment, the piston bolt 5 is divided into a first member 131 and a second member 132, and the first small diameter portion 12 and the large diameter portion 13 of the common passage 11 are the first member. Since it was formed in 131 and the second small diameter portion 14 of the common passage 11 was formed in the second member 131, each axial passage (first small diameter portion 12, large diameter portion 13) of the common passage 11 was formed during processing of the common passage 11. , And the approach to the second small diameter portion 14) is easy. As a result, the common passage 11 can be machined by a general-purpose construction method and a tool, and the man-hours for the piston bolt 5 can be reduced. As a result, the productivity of the piston bolt 5 is improved, and the manufacturing cost of the shock absorber 1 can be reduced. Moreover, since the approach to each axial passage is easy, the man-hours required for inspection can be reduced.

Further, in the first embodiment, it is possible to reduce the cutting process by using the near shape processing (molding) as the material of the first member 131, and it is possible to reduce the processing man-hours. Further, in the first embodiment, the convex portion 135 of the second member 132 is press-fitted into the large diameter portion 13 of the first member 131, and the upper end surface 134 (one end surface in the axial direction) of the second member 132 is of the first member 131. Since the first member 131 and the second member 132 are coupled by abutting on the lower end surface 133 (the other end surface in the axial direction), the coaxiality of the common passage 11 and the first small diameter portion as the spool sliding surface The squareness between the 12 and the end surface 136 of the convex portion 135 as the valve seat surface can be secured.

Further, in the first embodiment, the lower end surface 133 (the other end surface in the axial direction) of the first member 131 and the upper end surface 134 (one end surface in the axial direction) of the second member 132 are in contact with the first member 131. The abutting portion 137 with the second member 132 was brazed. Since brazing is less deformed by heat, deformation due to heat is suppressed, and there is no need for cutting for the purpose of shape correction after brazing, so that an increase in man-hours can be suppressed.

(Second Embodiment) Next, the second embodiment will be described with reference to FIG. Here, the differences from the first embodiment will be described. In addition, the same title and reference numeral are given to the common part with the first embodiment.
In the first embodiment, the piston bolt 5 is divided into a first member 131 and a second member 132, and the first small diameter portion 12 and the large diameter portion 13 of the common passage 11 are formed in the first member 131. , The second small diameter portion 14 of the common passage 11 was formed in the second member 131.

On the other hand, in the second embodiment, the piston bolt 5 is divided into the first member 141 and the second member 142, and the first small diameter portion 12 of the common passage 11 is formed in the first member 141, which is common. The large-diameter portion 13 and the second small-diameter portion 14 of the passage 11 are formed in the second member 142. The first member 141 is made of a cylindrical sleeve-shaped part, and the first small diameter portion 12 of the common passage 11 is formed on the inner circumference thereof. On the other hand, the upper end (one end in the axial direction) of the large diameter portion 13 opens in the recess 10 of the second member 142.

The first member 141 is provided with a radial passage 64 formed in the second member 142 and a passage 145 and a passage 146 for communicating with the radial passage 69. Further, the axial length of the first member 141 is set shorter than the axial length of the large diameter portion 13 formed on the second member 142. The axial length of the large diameter portion 13 of the piston bolt 5 is the difference between the axial length of the large diameter portion 13 of the second member 142 and the axial length of the first member 141.

Then, in order to connect the first member 141 and the second member 142 to form the piston bolt 5, the first member 141 is inserted from the upper end (one end) of the large diameter portion 13 of the second member 142, and the first member is first. The first member 141 is press-fitted into the large diameter portion 13 of the second member 142 until the upper end surface 143 of the member 141 is flush with the bottom surface of the recess 10 of the second member 142. As a result, a large diameter portion 13 for accommodating the valve body 85 of the valve spool 82 (valve shaft) is formed between the first small diameter portion 12 and the second small diameter portion 14 of the piston bolt 5.

It should be noted that the sealing property of the fing surface 144 between the first member 141 and the second member 142 by press-fitting may be ensured by joining, adhering, or the like.
According to the second embodiment, it is possible to obtain the same effect as that of the first embodiment described above.

(Third Embodiment) Next, the third embodiment will be described with reference to FIG. Here, the differences from the first and second embodiments will be described. The same titles and symbols are given to the common parts with the first and second embodiments.
In the third embodiment, the piston bolt 5 is divided into a first member 151 and a second member 152, and the first small diameter portion 12 and the large diameter portion 13 of the common passage 11 are formed in the first member 151. , The second small diameter portion 14 of the common passage 11 was formed in the second member 142. In this respect, the third embodiment is the same as the first embodiment.

The second member 152 has a shaft shape, and a flange 153 is formed at the other end in the axial direction. One end of the second small diameter portion 14 of the common passage 11 opens at one end in the axial direction of the second member 152. On the other hand, the other end of the large diameter portion 13 of the common passage 11 opens at the other end in the axial direction of the first member 151. A counterbore 154 into which the flange 153 of the second member 152 is fitted is formed on the peripheral edge of the opening of the large diameter portion 13 at the other end in the axial direction of the first member 152.

The second member 152 is provided with a radial passage 34 formed in the first member 151 and a passage 155 and a passage 156 for communicating with the radial passage 39. Further, the axial length of the second member 152 is set shorter than the axial length of the large diameter portion 13 formed on the first member 151. The axial length of the large diameter portion 13 of the piston bolt 5 is the difference between the axial length of the large diameter portion 13 of the first member 151 and the axial length of the second member 152.

Then, in order to connect the first member 151 and the second member 152 to form the piston bolt 5, the second member 152 is inserted from the lower end (the other end) of the large diameter portion 13 of the first member 151, and the second member 152 is inserted. The second member 152 is first placed until the flange 153 of the second member 152 is fitted into the counterbore 154 of the first member 151 and the lower end surface 157 of the second member 152 is flush with the lower end surface 158 of the first member 151. It is press-fitted into the large diameter portion 13 of the member 151. As a result, a large diameter portion 13 for accommodating the valve body 85 of the valve spool 82 (valve shaft) is formed between the first small diameter portion 12 and the second small diameter portion 14 of the piston bolt 5.

It should be noted that the sealing property of the fing surface 159 between the first member 151 and the second member 152 by press-fitting may be ensured by joining, adhering, or the like.
According to the third embodiment, it is possible to obtain the same effects as those of the first and second embodiments described above.

The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

This application claims priority based on Japanese Patent Application No. 2020-010063 filed on January 24, 2020. The entire disclosure, including the specification, claims, drawings, and abstract of Japanese Patent Application No. 2020-010063 filed on January 24, 2020, is incorporated herein by reference in its entirety.

1 shock absorber, 2 cylinder, 2A cylinder upper chamber, 2B cylinder lower chamber, 3 piston, 5 piston bolt, 11 common passage, 15 piston rod, 19 extension side passage, 20 contraction side passage, 23 extension side main valve, 26 extension Side back pressure chamber, 53 contraction side main valve, 56 contraction side back pressure chamber, 81 pilot valve (piston valve), 82 valve spool (valve shaft), 85 valve body, 88 valve spring, 91 solenoid (actor), 115th 1 valve part, 116 1st valve seat, 117 2nd valve part, 118 2nd valve seat

Claims

It is a damping force adjustment type shock absorber, and the shock absorber is
Cylinder in which working fluid is sealed and
A piston that is slidably fitted in the cylinder and divides the inside of the cylinder into two chambers.
A piston rod with one end connected to the piston and the other end extending outward from the cylinder.
The extension side passage and the contraction side passage provided in the piston,
A piston bolt inserted into the shaft hole of the piston and
The extension side main valve provided in the extension side passage and the extension side main valve
An extension side back pressure chamber that adjusts the valve opening pressure of the extension side main valve, and an extension side back pressure chamber.
The contraction side main valve provided in the contraction side passage and
The contraction side back pressure chamber that adjusts the valve opening pressure of the contraction side main valve, and
A common passage communicating the extension side back pressure chamber and the contraction side back pressure chamber,
A valve shaft movably provided in the common passage and
A valve spring that urges the valve shaft in the valve opening direction,
A pilot valve that controls the flow of oil and liquid in the common passage,
An actuator for controlling the movement of the valve shaft is provided.
At one end of the valve body in the axial direction of the valve shaft, a first valve portion that restricts the flow of working fluid to and from the first valve seat formed on the piston bolt is provided when the actuator is not energized.
On the other end side in the axial direction of the valve body, a second valve portion that restricts the flow of the working fluid with the second valve seat formed on the piston bolt when the actuator is energized is provided.
The piston bolt is composed of a first member and a second member.
The first valve seat is formed on the first member.
A shock absorber characterized in that the second valve seat is formed on the second member.
In the shock absorber according to claim 1,
The common passage has a large diameter portion in which the valve body is housed, a first small diameter portion that opens on one side in the axial direction of the large diameter portion, and a second small diameter portion that opens on the other side in the axial direction of the large diameter portion. The part and is provided,
The first small diameter portion and the large diameter portion are provided on either the first member or the second member.
The second small diameter portion is a shock absorber provided on either the first member or the second member, whichever is the other.
In the shock absorber according to claim 1 or 2.
In the first member, the first small diameter portion is formed at one end in the axial direction, and the large diameter portion is formed at the other end in the axial direction.
A shock absorber characterized in that one end of the second member is inserted into and fixed to the large diameter portion.
In the shock absorber according to any one of claims 1 to 3,
A shock absorber characterized in that one end in the axial direction of the second member is the second valve seat.
In the shock absorber according to any one of claims 1 to 4.
The second member has a convex portion formed on the inner peripheral side of one end surface in the axial direction.
A shock absorber characterized in that the convex portion is inserted into and fixed to the large diameter portion.
In the shock absorber according to claim 5,
A shock absorber characterized in that the one end surface in the axial direction of the second member and the other end surface in the axial direction of the first member are in contact with each other.
In the shock absorber according to any one of claims 1 to 4.
A shock absorber characterized in that a flange abutting on the large diameter portion of the first member is formed at the other end in the axial direction of the second member.
In the shock absorber according to claim 1,
The first small diameter portion is formed on the first member.
The large-diameter portion and the small-diameter portion are formed on the second member.
The first member is a shock absorber characterized by being a hollow rod inserted into the large diameter portion of the second member.